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Week 5: Troubleshooting and Running Sediment Samples

One of th other interns, Jean-Paul, came back to the lab with sediment samples from nearby, so we began this week by running tests on his samples. I spiked two samples of the sediment with 2-CAP to see how it would react with this particular sediment type. For each sample, I would spike with 2-CAP, shake the tube for about a minute, withdraw about 1.5 mL to fill a microfuge tube, centrifuge the sample, then withdraw the supernatant to run on the HPLC. Dimin said that we should also filter the samples to make sure that nothing clogs the HPLC. At first the filters gave extra peaks on the HPLC even though they're supposed to be unreactive. Dimin and I were unsure why so I ran filtered and unfiltered samples of 2-CAP, AP, and 2-CPE to see how much of a difference filtering made on our results. 

All of the filtered samples had a reduced peak area and extra peaks showed up on the HPLC, so Dimin and I had to figure out why or use more expensive filters (of which we were running out). It turns out that Dimin and I weren't using the filters as instructed by the manufacturer, so when we followed their instructions exactly the extra peaks stopped coming out and the peak areas became stable. 

I respiked the old T0 and ran a new T0 on JP's sediment sample since I didn't put the right amount of 2-CAP in the first sample I made. Even though the old T0 didn't have the right amount of 2-CAP at first and I had to respike it with 2-CAP, I sill ran samples of it onthe HPLC to see how fast the reaction was going. The reaction seems pretty slow since there's little change in the 2-CAP peak area within the first 4 hours. The new T0 I made in the glovebox so that it would be anaerobic. I spiked the sample with 2-CAP but the HPLC started leaking so I couldn't analyze any samples. Instead I just took samples at different time intervals and kept the samples in the refrigerator. On Monday, once the HPLC is working again, I'll run the samples that I took on Friday (also the ones that Dimin took on Saturday and Sunday).